Ethylene, one of the most widely used feedstock molecules in the petrochemical industry, is usually obtained via steam cracking and thermal decomposition of ethane. See Matar, S.; Hatch, L. F. chemistry of petrochemical processes, 2nd ed.; Gulf Publishing Company: Texas, 2000. The similar molecular sizes and volatilities make the separation of ethylene/ethane mixtures one of the most challenging chemical separations at large scale. See Eldridge, R. B. Ind. Eng. Chem. Res. 1993, 32:2208. Current technology uses cryogenic distillation performed under the condition of high pressure (23 bar) and low temperature (−25° C.), resulting in an extremely cost and energy intensive process. See Rege, S. U.; Padin, J.; Yang, R. T. AIChE J. 1998, 44:799. Extensive efforts to develop low energy approaches for efficient ethylene/ethane separation at higher temperature and normal atmospheric pressure have focused on membrane separation, organic solvent-based sorbents, and porous solid adsorbents. For membrane separations, see Zhu et al., J. Am. Chem. Soc. 2012, 134:104784. For organic solvent-based sorbents, see Safarik, et al., Ind. Eng. Chem. Res. 1998, 37:2571. For porous solid sorbents, see Yang, R. T. Adsorbents: Fundamentals and Applications; John Wiley & Sons, Inc.: New Jersey, 2003. Among these approaches, porous solid adsorbents attract particular interest because of their great potential to afford much lower cost and energy consumption.
Over the past decade, advanced porous materials such as metal-organic frameworks (MOFs) and porous organic polymers (POPs) [e.g. porous aromatic frameworks (PAFs), conjugated microporous polymers (CMPs), porous polymer networks (PPNs), porous organic frameworks (POFs)] have been explored as new classes of solid adsorbents for applications in gas storage, gas separation, carbon capture, catalysis, etc. In comparison with MOFs, POPs, despite the amorphous nature for most of them, lack preferential binding sites for ethylene molecules leading to poor ethylene/ethane adsorption selectivity.
It is an object of this disclosure to provide improved porous materials for olefin/paraffin separations.
It is an additional object of this disclosure to provide materials for olefin/paraffin separation with high olefin uptake capacities.
It is a further object of this disclosure to provide materials for olefin/paraffin separation with high selectivities for olefins.
It is also an object of this disclosure to provide methods of making improved porous materials for olefin/paraffin separations.
An object of this disclosure is also to provide methods of olefin/paraffin separation using improved porous materials.